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What is a frequency distribution?
 It summarizes the data into a more useful form.
 Condenses the data.
 Mostly seen as Table 1 in clinical trials

How do you calculate the relative frequency?
Pick a category and divide that by the total # of results to get a decimal.

What graph do u use to graph a frequency distribution?
 Histogram  no spaces between the bars
 Excel can't make histogram

For the histogram what goes on the the horizontal axis?
Class boundaries, categories, etc

What goes on the vertical axis of a histogram?
Frequency

What levels of measurement are used in histograms?
Ordinal, Interval, and ratio

What are bar/pie graphs used for?
Used for nominal and ordinal or both

In a bar or pie chart what shows the frequency or percentage for each category?
 Bar Chart  height of bar
 Pie Chart  pie slice
 The bigger the higher frequency

Nominal and Ordinal together?
Categorical data

Interval and Ratio together?
Continuous

What is a true bar chart?
 The bars go left to right not up to down.
 Has Spaces

What do you use to graph for a histogram, bar, and pie chart?
 Histogram  categorie + frequency
 Bar  categorie + percentage
 Pie  categorie + percentage

What is the mean?
Average of the data

Technically what is mean, mode, median?
 Averages
 This is your First Name

What is your last name?
Variation

What is your middle name?
Quartiles


What is the population mean?
Greek M

What is the most common measure of central tendency?
Mean  affected by outliers

What is mean?
 The fulcrum  from jeoprady
 Its continuous data  interval and ratio

What type of mean is used in stats?
Arithmetic mean

What is the median?
Robust measure of central tendency because not affected by outliers

What must be done to get the median?
Arrange it in numerical order first

What is mode?
 Value occurs most often
 Not effected by outlier
 For numerical or categorical data

How many modes can there be?
None, 1, or multiple (use commas arrange small to big)

What is the best for measurement?
 Mean only if no outliers
 Then Median
 Only mode if categorical data

What quartiles are measures of noncentral location?
Q1 and Q3

What quartile gives you the median or measure of central tendency?
Q2

What measures variation?
 Range (large  small)
 Interquartile Range
 Variance
 Standard Deviation (most important)

Does range provide a good value?
No, it ignores the way in which data are distributed

What is interquartile range (midspread)?
 Measure of variation
 Difference between third and first quartile
 Not affected by extreme values
 Goes with the median

What is variance?
 Measure of Variation
 Shows variation about the mean

What is standard deviation?
 Measure of Variation
 Shows variation of the mean
 Sq root of the variance

What is standard error?
 To understand variation within many samples
 Will always be smaller than st. dev.

What is the Empirical Rule?
 Data is bellshaped (symmetric) for the population or LARGE samples
 1. M = 1o contains about 68% of the values
 2. 2o = 95%
 3. 3o = 99.7%

What are the 2 types of distributions?
 Variable of interest distribution (Normal/Skewed)
 Probablility Distribution (Normal/NonNormal)

What is the central limit theorem?
If the sample size gets large enough the sampling distribution becaomes almost normal regardless of shape of population because your getting closer and closer to to the population size

What is normal distribution?
 Bell Shaped
 Symmetrical
 Mean, mode, median all =
 Location determined by mean
 Spread determined by st dev.
 Has infinite theoretical range: all  to + # (infinity)

What is the standard normal?
Converting the normal distribution into Z units

What does the t value depends on?
 Degrees of Freedom
 d.f = n1

Whats the difference between tdistributions and normal distribution graphs?
 Same bell shape and symmetric but fatter tails  means triple M = 0 but std dev depends on df
 Smaller the DF the flatter the graph

How do you know how many tails in the T test?
 Null Hypothesis is of Equality (=)  2 tail test
 Non inferiority (< , >)  1 tail

What is the difference between Fdistributions and Tdistributions?
 DF  2 for F
 One tailed only for F
 Skewed to right for F

What can you use Chi square test for?
 Small Sample Size continuous data
 Badly skewed data
 Nominal Data
 Ordinal Data

